transmission is an indication of proper
operation. The lack of sidetone is an
indication of failure.
6. If squelch operation is desired, rotate
squelch control fully clockwise. With
no signal present, rotate squelch
control counterclockwise until the
background noise is reduced to a
comfortably audible level or until the
control is fully counterclockwise. After
a short delay, the receiver will mute.
If background noise was reduced to a
comfortable level before the audio was
muted, the radio is equipped with a
combination RF gain/squelch feature and
control should be left at setting desired in
the above step. If control was rotated to
the full counterclockwise position with no
system incorporates the standard squelch
7. Rotate squelch knob clockwise one
step at a time until background noise
is heard, and squelch is broken. Set
counterclockwise. After a short delay,
the receiver will mute.
8. If a new frequency is desired, repeat
steps 2 through 7.
d. Operator Maintenance.
Do not touch antenna or antenna feedline
when radio is transmitting. Painful RF
burns and possibly death may result from
high RF voltages.
(1) Fault Clearing. After the tune cycle has
been completed, the normal tune tone should
disappear. Should it fail to disappear, an interrupted
tone, beeping, will occur approximately 8 seconds
after the tune cycle was initiated. This beeping
indicates a fault condition. To clear the fault, initiate a
new tune cycle by either turning the mode selector to
OFF and back to the operating mode, or turning any
frequency selector away from and back to the
operating frequency. The tune tone should be present
for approximately 3 to 6 seconds, and then disappear.
If the beeping recurs, try the clearing procedure a
second time. If a fault is still indicated, a unit failure is
(2) RF Test. To isolate a malfunction to a
faulty unit or cable, perform the following procedure.
1. Set squelch control fully clockwise and
20.701.0 MHz, and check for a 1-kHz
tone. Select LSB, 20.699.0 MHz, and
check for a 1-kHz tone. Select CW,
20.698.0 MHz, and check for a 1-kHz
tone in receiver.
2. RF TEST Lamp Check, system not
keyed. Set the mode switch to the RF
a. If the RF TEST lamp does not
illuminate, the lamp is defective or
the receiver-exciter is faulty.
b. If the RF TEST lamp blinks for
more than 1 minute, the receiver-
exciter is faulty.
c. If the RF TEST lamp illuminates
immediately or after an initial
period of blinking, the RF TEST
3. Set the mode switch to the RF TEST
position. Change frequency selection
to any frequency and key the system
momentarily. Observe the RF TEST
lamp during the tune cycle while the
tune tone is audible. Normal tune
time is 3 to 8 seconds.
4. System Does Not Complete Tune
Cycle. If no tune tone is heard after
initial keying, the fault is in the
receiver-exciter, the PTT key to the
receiver-exciter is faulty, or the exciter
tune line between the receiver-exciter
and pa-coupler is faulty.